Optical module for transmitting optical signal

ABSTRACT

An optical module comprises: a housing; a first incident surface mounted on the housing for receiving an optical signal converted from an electrical signal; a first output surface mounted on the housing for exporting the optical signal from the first incident surface; a second incident surface mounted on the housing for receiving another optical signal to be converted to another electrical signal; and a second output surface mounted on the housing for exporting the another optical signal from the second incident surface. An aperture of the first incident surface is smaller than an aperture of the second incident surface.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical module, and moreparticularly to an optical module for improving optical signaltransmission.

2. Description of Related Arts

An optical transceiver is used in optical networking for conversionbetween an optical signal and an electrical signal.

Generally, an optical transceiver comprises an optical module having aTOSA (Transmitter Optical Subassembly) for receiving an optical signalconverted from an electrical signal by a VCSEL and transmitting theoptical signal to a waveguide, and a ROSA (Receiver Optical Subassembly)for receiving an optical signal from another waveguide and transmittingthe optical signal to a photodiode which converts the optical signal toan electrical signal. Between the optical signal from the VCSEL to thewaveguide and the optical signal from the another waveguide to thephotodiode are needed two lenses for handling the optical signals.

U.S. Pat. No. 8,195,017 discloses a consumer input/output (CIO) opticaltransceiver module for use in an active optical cable. The transceivermodule includes two singlet laser diodes and two singlet photodiodes ina row, instead of costly parallel arrays of laser diodes and parallelarrays of photodiodes that are used in known active optical cables, forproviding two high-speed transmit channels and two high-speed receivechannels, respectively. Correspondingly arranged is an optics systemmodule having lenses formed therein for coupling light between opticalfibers and the laser diodes and the photodiodes.

U.S. Pat. No. 7,212,698, issued to Bapst et al. on May 1, 2007,discloses a method of processing a circuit board having one or moreassociated optical waveguides, comprising providing and using one ormore etch stop layers in proximate to the one or more waveguides toprovide one or more cavities having a defined positioning and depth foralignment of one or more optical components. The optical component isselected from the group consisting of opto-electronic modules, lenses,turning mirrors and/or their combination. Also disclosed is staggeringof turning mirrors and lenses to increase waveguide density.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved opticalmodule. To achieve the this object, an optical module comprises: ahousing; a first incident surface mounted on the housing for receivingan optical signal converted from an electrical signal; a first outputsurface mounted on the housing for exporting the optical signal from thefirst incident surface; a second incident surface mounted on the housingfor receiving another optical signal to be converted to anotherelectrical signal; and a second output surface mounted on the housingfor exporting the another optical signal from the second incidentsurface. An aperture of the first incident surface is smaller than anaperture of the second incident surface.

Other objects, features and advantages of the invention will be apparentfrom the following detailed description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of an optical module in accordance with thepresent invention;

FIG. 2 is a view similar to FIG. 1, but from another aspect;

FIG. 3 is a view similar to FIG. 1, but from the third aspect; and

FIG. 4 is a cross section view of the optical module of FIG. 3 takenalong line 4-4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to a preferred embodiment of thepresent invention.

Referring to FIGS. 1 to 4, an optical module 100 for being used for anoptical transmitter or transceiver in accordance with the presentinvention comprises a housing 10, a first lens array 20 as a route whichan optical signal converted to an electrical signal and a second lensarray 30 as a route which an electrical signal converted to an opticalsignal.

Referring to FIGS. 1 to 4, the housing 10 comprises a main portion 11for mounting to the first and second lens arrays 20, 30. The mainportion 11 is a rectangular and has a first surface 11 and a secondsurface 12 opposite to the first surface 11. Two pairs of flanges 112,122 extend outwardly from two lateral sides of the first surface 11 andsecond surface 12, respectively. A first column 113 is defined betweentwo flanges 112 on the first surface 11 and extends outwardly from thefirst surface 11. A pair of second columns 123 are defined between twoflanges 122 on the second surface 12 and extends outwardly from thesecond surface 12 for positioning the housing 10. A through hole 114 isrun through the first and second surfaces 11, 12.

The first lens array 20 and the second lens array 30 parallel to thesecond lens array 20 are mounted on the housing 10. The first lens array20 and the second lens array 30 are vertical to two pairs of flanges112. The first lens array 20 has a number of first lenses 2 arranged ina row. The second lens array 30 has a number of second lenses 3 arrangedin a row. The housing 1 is molded on the periphery of the first lensarray 20 and the second lens array 30. From a view of a verticaldirection of the first and second lens arrays 20, 30, the first lenses20 and the second lenses 30 are staggered each other. Each first lens 2has a first incident surface 21 for receiving the optical signaltransmitting into the lens 2 and a first output surface 22 for exportingthe optical signal transmission from the lens 2. The first incidentsurface 21 and the first output surface 22 are mounted or constituted onthe housing 1. The first incident surface 21 and the first outputsurface 22 are respectively a curved surface which belong to anelliptical or circle structure and bulged outwardly. The curved surfacemay be a convex lens. The mid portions of the first incident and outputsurface 21, 22 are bulged highest. Each second lens 3 has a secondincident surface 31 for receiving an optical signal transmitting intothe second lens 3 and a second output surface 32 for exporting theoptical signal transmission from the second lens 3. The second incidentsurface 31 and the second output surface 32 are mounted or constitutedon the housing 1, too. The second incident surface 31 and the secondoutput surface 32 are respectively similar to the structures of thefirst incident and output surface 21, 22, that is an curved surface ofthe second incident or output surface 31, 32 which belong to anelliptical or round structure and bulged outwardly. The curved surfacecan be another convex lens. The mid portions of the second incident andoutput surface 31, 32 are bulged highest. In other embodiments, thefirst incident and output surface 21, 22 may be not formed on a lens 2,the first incident and output surface 21, 22 are formed on two differentlenses. The second incident or output surface 31, 32 are formed on twodifferent lenses. The first incident and output surface 21, 22 and thesecond incident or output surface 31, 32 are exposed from the first andsecond surface 11, 12 of the housing 1, respectively.

The first incident surface 21 of the first lens 2 and the second outputsurface 32 of the second lens 3 are located on a first surface 11 of thehousing. The first output surface 22 of the first lens 2 and the secondincident surface 31 of the second lens 3 are located on a second surface12 of the housing 1. An approximately 45 degrees angle is formed betweenthe first incident surface 21 and first output surface 22 of the firstlens 2, and an approximately 45 degrees angle is formed between thesecond incident surface 31 and second output surface 32 of the secondlens 3.

When the optical module 100 is used for the optical transmitter ortransceiver, and the optical transmitter or transceiver is needed to anoptical signal be converted from an electrical signal, the opticalsignal be converted from the electrical signal by a vertical cavitysurface emitting laser (VCSEL) firstly, the first incident surface 21receives the optical signal from VCSEL mounted on the first surface 11of the housing 1, and the optical signal goes through the first lens 2and exports the first output surface 22 toward a waveguide, secondly.When the optical transmitter or transceiver is needed to an opticalsignal be converted to an electrical signal, the optical signal whichcomes from electrical signal is converted to by another waveguide issent toward a photodiode, the second incident surface 31 receives theoptical signal from the waveguide mounted on the second surface 12 ofthe housing 1, and the optical signal goes through the second lens 3 andexports the second output surface 32 toward the photodiode.

The term “aperture” refers to the size of receiving an optical signal orhandling the optical signal. If the incident or output surface of firstor second lens 2, 3 is circle, the aperture is as the diameter of theincident or output surface; and if the incident or output surface iselliptical, the aperture is as the area of the incident or outputsurface. After divergence optical signal is received by the aperture ofthe first or second incident surface 21, 31, the optical signal can beparallel to each other or gather inwardly. After the divergence opticalsignal is received by the area of the outside of the aperture of thefirst or second incident surface 21, 31, the divergence optical signalis still divergence outwardly, and of which angle is increased. Due tothe VCSEL providing a small hole to emit the optical signal, and thedivergence angle of the optical signal from the VCSEL is small. So, thesmall aperture of the first incident surface 21 is provided to receivethe small divergence angle optical signal. After the parallel orgathering the optical signal in the lens 2 being exported by the firstoutput surface 22, the optical signal can gather inwardly again or focuson a point and transit toward the waveguide. The hole of the VCSEL isvertical to the first and second surface of housing 1, and the hole ofthe waveguide is extending along the first and second surface of housing1. Through the optical signal is sent by the first lens 2 and the secondlens 3, the route of optical signal before the first or second lens 2, 3is vertical roughly to the route the route of the optical signal whichis exported from the first or second lens 2, 3.

Due to the waveguide providing a bigger hole than the VCSEL to emit anoptical signal, the divergence angle of the optical signal from thewaveguide is bigger. So, the aperture of the second incident surface 31bigger than the first incident surface's 21 is provided to receive thebigger divergence angle optical signal. After the parallel or gatheringthe optical signal in the second lens 3 being exported by the secondoutput surface 32, the optical signal can gather inwardly again or focuson a point and transit toward the photodiode. As the divergence angle orarea of the optical signal sent by the first lens 2 is smaller thansecond lens 3, as the aperture of the first output surface 22 of thefirst lens 2 is smaller an aperture of the second output surface 32 ofthe second lens 3.

According to the divergence angle that the optical signal arrival at thefirst or second incident 21, 31 of the lenses 2, 3, the optical module100 is confirmed that the aperture area of the first lens 2 or secondlens 3. The optical module 100 has a big aperture for receiving the bigdivergence angle of the optical signal, and has a small aperture forreceiving the small divergence angle of the optical signal.

It is to be understood, however, that even though numerouscharacteristics of the present invention have been set forth in theforegoing description, together with details of the structure andfunction of the invention, the disclosure is illustrative only, andchanges may be made in detail, especially in matters of shape, size, andarrangement of parts within the principles of the invention to the fullextent indicated by the broad general meaning of the terms in which theappended claims are expressed.

What is claimed is:
 1. An optical module comprising: a housing; a firstincident surface mounted on the housing for receiving an optical signalconverted from an electrical signal; a first output surface mounted onthe housing for exporting the optical signal from the first incidentsurface; a second incident surface mounted on the housing for receivinganother optical signal to be converted to another electrical signal; anda second output surface mounted on the housing for exporting the anotheroptical signal from the second incident surface; wherein an aperture ofthe first incident surface is smaller than an aperture of the secondincident surface.
 2. The optical module as recited in claim 1, whereinan approximately 45 degrees angle is formed between the first incidentsurface and the first output surface, and an approximately 45 degreesangle is formed between the second incident surface and the secondoutput surface.
 3. The optical module as recited in claim 1, wherein thefirst incident surface and the first output surface constitute a firstlens, and the second incident surface and the second output surfaceconstitute a second lens.
 4. The optical module as recited in claim 3,wherein a plurality of first lenses are provided to form a first lensarray arranged in a row, and a plurality of second lenses are providedto form a second lens array arranged in a row.
 5. The optical module asrecited in claim 4, wherein the first incident surface of the first lensand the second output surface of the second lens are located on a firstsurface of the housing.
 6. The optical module as recited in claim 5,wherein the first output surface of the first lens and the secondincident surface of the second lens are located on an opposite secondsurface of the housing.
 7. The optical module as recited in claim 1,wherein the first incident surface of the first lens collimate theoptical signals.
 8. The optical module as recited in claim 1, whereinthe second incident surface of the second lens collimate the opticalsignals.
 9. The optical module as recited in claim 8, wherein the firstand second lenses are staggered.
 10. The optical module as recited inclaim 1, wherein an aperture of the first output surface is smaller thanan aperture of the second output surface.
 11. An optical modulecomprising: a housing defining a lengthwise direction and a transversedirection perpendicular to each other and both perpendicular to avertical direction along which opposite first and second faces areopposite to each other; a first lens array including a plurality offirst lenses thereof and a second lens array including a plurality ofsecond lenses thereof, both of which are associated with the housing andspace from each other in said lengthwise direction while each arrangedin said transverse direction; the first lens defining a first lighttransmission path with a first incident surface around the second facefor receiving a first optical signal which is converted from anelectrical signal, and with a first output surface around the first facefor transmitting the first optical signal to a corresponding waveguidearound the first face; and the second lens defining a second lighttransmission path with a second incident surface around the first facefor receiving a second optical signal from a corresponding waveguidearound the first face, and with a second output surface around thesecond face for transmitting the second optical signal toward aphotodiode for converting the second optical signal to an electricalsignal; wherein the first lens is configured to be different from thesecond lens.
 12. The optical module as claimed in claim 11, wherein thefirst lens defines a first reflection curved area around the firstoutput surface and the second lens defines a second reflection curvedarea around the second incident surface under condition that the firstreflection curved area and the second reflection curved area are sizeddifferent from each other.
 13. The optical module as claimed in claim12, wherein said first reflection curved area is smaller than the secondreflection curved area.
 14. The optical module as claimed in claim 11,wherein the first lens is smaller than the second lens.
 15. The opticalmodule as claimed in claim 14, wherein the first lens is configured tobe a converging type while the second lens is configured to be aparallel type.
 16. The optical module as claimed in claim 11, whereinthe first lens defines a first curved area around the first incidentsurface and the second lens defines a second curved area around thesecond incident surface under condition that the first reflection curvedarea and the second reflection curved area are sized different from eachother.
 17. The optical module as claimed in claim 16, wherein the firstcurved area is smaller than the second curved area.